networkd: tie links to rtnl rather than udev

This essentially swaps the roles of rtnl and udev in networkd. After this
change libudev is only used for waiting for udev to initialize devices and
to get udev-specific information needed for some [Match] attributes.

This in particular simplifies the code in containers where udev is not really
useful, but also simplifies things and reduces round-trips in the non-container
case.

1 files changed, 133 insertions, 120 deletions

diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index f179af332c..319f2904c0 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -24,7 +24,9 @@
 
 #include "networkd.h"
 #include "libudev-private.h"
+#include "udev-util.h"
 #include "util.h"
+#include "virt.h"
 #include "bus-util.h"
 #include "network-internal.h"
 
@@ -33,41 +35,53 @@
 static int ipv4ll_address_update(Link *link, bool deprecate);
 static bool ipv4ll_is_bound(sd_ipv4ll *ll);
 
-int link_new(Manager *manager, struct udev_device *device, Link **ret) {
+static int link_new(Manager *manager, sd_rtnl_message *message, Link **ret) {
         _cleanup_link_free_ Link *link = NULL;
-        const char *ifname;
-        int r;
+        uint16_t type;
+        char *ifname;
+        int r, ifindex;
 
         assert(manager);
         assert(manager->links);
-        assert(device);
+        assert(message);
         assert(ret);
 
+        r = sd_rtnl_message_get_type(message, &type);
+        if (r < 0)
+                return r;
+        else if (type != RTM_NEWLINK)
+                return -EINVAL;
+
+        r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
+        if (r < 0)
+                return r;
+        else if (ifindex <= 0)
+                return -EINVAL;
+
+        r = sd_rtnl_message_read_string(message, IFLA_IFNAME, &ifname);
+        if (r < 0)
+                return r;
+
         link = new0(Link, 1);
         if (!link)
                 return -ENOMEM;
 
         link->manager = manager;
-        link->state = _LINK_STATE_INVALID;
-
-        link->ifindex = udev_device_get_ifindex(device);
-        if (link->ifindex <= 0)
-                return -EINVAL;
+        link->state = LINK_STATE_INITIALIZING;
+        link->ifindex = ifindex;
+        link->ifname = strdup(ifname);
+        if (!link->ifname)
+                return -ENOMEM;
 
         r = asprintf(&link->state_file, "/run/systemd/network/links/%"PRIu64,
                      link->ifindex);
         if (r < 0)
                 return -ENOMEM;
 
-        ifname = udev_device_get_sysname(device);
-        link->ifname = strdup(ifname);
-
         r = hashmap_put(manager->links, &link->ifindex, link);
         if (r < 0)
                 return r;
 
-        link->udev_device = udev_device_ref(device);
-
         *ret = link;
         link = NULL;
 
@@ -1036,7 +1050,6 @@ static int link_update_flags(Link *link, unsigned flags) {
         int r;
 
         assert(link);
-        assert(link->network);
 
         if (link->state == LINK_STATE_FAILED)
                 return 0;
@@ -1060,13 +1073,12 @@ static int link_update_flags(Link *link, unsigned flags) {
 
         link->flags = flags;
 
-        if (flags_added & generic_flags)
-                log_debug_link(link, "link flags gained: %#.8x",
-                               flags_added & generic_flags);
-
-        if (flags_removed & generic_flags)
-                log_debug_link(link, "link flags lost: %#.8x",
-                                flags_removed & generic_flags);
+        if (!link->network)
+                /* not currently managing this link
+                   we track state changes, but don't log them
+                   they will be logged if and when a network is
+                   applied */
+                return 0;
 
         if (flags_added & IFF_UP)
                 log_info_link(link, "link is up");
@@ -1083,6 +1095,14 @@ static int link_update_flags(Link *link, unsigned flags) {
         else if (flags_removed & IFF_RUNNING)
                 log_debug_link(link, "link is not running");
 
+        if (flags_added & generic_flags)
+                log_debug_link(link, "ignored link flags gained: %#.8x",
+                               flags_added & generic_flags);
+
+        if (flags_removed & generic_flags)
+                log_debug_link(link, "ignored link flags lost: %#.8x",
+                                flags_removed & generic_flags);
+
         if (carrier_gained) {
                 log_info_link(link, "gained carrier");
 
@@ -1180,10 +1200,12 @@ static int link_enslaved(Link *link) {
         assert(link->state == LINK_STATE_ENSLAVING);
         assert(link->network);
 
-        r = link_up(link);
-        if (r < 0) {
-                link_enter_failed(link);
-                return r;
+        if (!(link->flags & IFF_UP)) {
+                r = link_up(link);
+                if (r < 0) {
+                        link_enter_failed(link);
+                        return r;
+                }
         }
 
         if (!link->network->dhcp && !link->network->ipv4ll)
@@ -1231,7 +1253,7 @@ static int link_enter_enslave(Link *link) {
 
         assert(link);
         assert(link->network);
-        assert(link->state == _LINK_STATE_INVALID);
+        assert(link->state == LINK_STATE_INITIALIZING);
 
         link->state = LINK_STATE_ENSLAVING;
 
@@ -1323,95 +1345,11 @@ static int link_enter_enslave(Link *link) {
         return 0;
 }
 
-static int link_getlink_handler(sd_rtnl *rtnl, sd_rtnl_message *m,
-                                void *userdata) {
-        Link *link = userdata;
-        int r;
-
-        assert(link);
-        assert(link->ifname);
-
-        if (link->state == LINK_STATE_FAILED)
-                return 1;
-
-        r = sd_rtnl_message_get_errno(m);
-        if (r < 0) {
-                log_struct_link(LOG_ERR, link,
-                                "MESSAGE=%s: could not get state: %s",
-                                link->ifname, strerror(-r),
-                                "ERRNO=%d", -r,
-                                NULL);
-                link_enter_failed(link);
-                return 1;
-        }
-
-        link_update(link, m);
-
-        return 1;
-}
-
-static int link_getlink(Link *link) {
-        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL;
-        int r;
-
-        assert(link);
-        assert(link->manager);
-        assert(link->manager->rtnl);
-
-        log_debug_link(link, "requesting link status");
-
-        r = sd_rtnl_message_new_link(link->manager->rtnl, &req,
-                                     RTM_GETLINK, link->ifindex);
-        if (r < 0) {
-                log_error_link(link, "Could not allocate RTM_GETLINK message");
-                return r;
-        }
-
-        r = sd_rtnl_call_async(link->manager->rtnl, req, link_getlink_handler,
-                               link, 0, NULL);
-        if (r < 0) {
-                log_error_link(link,
-                               "Could not send rtnetlink message: %s", strerror(-r));
-                return r;
-        }
-
-        return 0;
-}
-
 static int link_configure(Link *link) {
         int r;
 
         assert(link);
-        assert(link->state == _LINK_STATE_INVALID);
-
-        r = link_getlink(link);
-        if (r < 0)
-                return r;
-
-        return link_enter_enslave(link);
-}
-
-int link_add(Manager *m, struct udev_device *device, Link **ret) {
-        Link *link = NULL;
-        Network *network;
-        int r;
-
-        assert(m);
-        assert(device);
-
-        r = link_new(m, device, &link);
-        if (r < 0)
-                return r;
-
-        *ret = link;
-
-        r = network_get(m, device, &network);
-        if (r < 0)
-                return r == -ENOENT ? 0 : r;
-
-        r = network_apply(m, network, link);
-        if (r < 0)
-                return r;
+        assert(link->state == LINK_STATE_INITIALIZING);
 
         if (link->network->ipv4ll) {
                 uint8_t seed[8];
@@ -1419,11 +1357,13 @@ int link_add(Manager *m, struct udev_device *device, Link **ret) {
                 if (r < 0)
                         return r;
 
-                r = net_get_unique_predictable_data(link->udev_device, seed);
-                if (r >= 0) {
-                        r = sd_ipv4ll_set_address_seed(link->ipv4ll, seed);
-                        if (r < 0)
-                                return r;
+                if (link->udev_device) {
+                        r = net_get_unique_predictable_data(link->udev_device, seed);
+                        if (r >= 0) {
+                                r = sd_ipv4ll_set_address_seed(link->ipv4ll, seed);
+                                if (r < 0)
+                                        return r;
+                        }
                 }
 
                 r = sd_ipv4ll_attach_event(link->ipv4ll, NULL, 0);
@@ -1463,10 +1403,84 @@ int link_add(Manager *m, struct udev_device *device, Link **ret) {
                 }
         }
 
+        return link_enter_enslave(link);
+}
+
+int link_initialized(Link *link, struct udev_device *device) {
+        Network *network;
+        unsigned flags;
+        int r;
+
+        assert(link);
+        assert(link->ifname);
+        assert(link->manager);
+
+        if (link->state != LINK_STATE_INITIALIZING)
+                return 0;
+
+        if (device)
+                link->udev_device = udev_device_ref(device);
+
+        log_debug_link(link, "link initialized");
+
+        r = network_get(link->manager, device, link->ifname, &link->mac, &network);
+        if (r < 0)
+                return r == -ENOENT ? 0 : r;
+
+        r = network_apply(link->manager, network, link);
+        if (r < 0)
+                return r;
+
         r = link_configure(link);
         if (r < 0)
                 return r;
 
+        /* re-trigger all state updates */
+        flags = link->flags;
+        link->flags = 0;
+        r = link_update_flags(link, flags);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int link_add(Manager *m, sd_rtnl_message *message, Link **ret) {
+        Link *link;
+        _cleanup_udev_device_unref_ struct udev_device *device = NULL;
+        char ifindex_str[2 + DECIMAL_STR_MAX(int)];
+        int r;
+
+        assert(m);
+        assert(message);
+        assert(ret);
+
+        r = link_new(m, message, ret);
+        if (r < 0)
+                return r;
+
+        link = *ret;
+
+        log_info_link(link, "link added");
+
+        if (detect_container(NULL) <= 0) {
+                /* not in a container, udev will be around */
+                sprintf(ifindex_str, "n%"PRIu64, link->ifindex);
+                device = udev_device_new_from_device_id(m->udev, ifindex_str);
+                if (!device) {
+                        log_warning_link(link, "could not find udev device");
+                        return -errno;
+                }
+
+                if (udev_device_get_is_initialized(device) <= 0)
+                        /* not yet ready */
+                        return 0;
+        }
+
+        r = link_initialized(link, device);
+        if (r < 0)
+                return r;
+
         return 0;
 }
 
@@ -1476,14 +1490,12 @@ int link_update(Link *link, sd_rtnl_message *m) {
         int r;
 
         assert(link);
-        assert(link->network);
         assert(m);
 
         if (link->state == LINK_STATE_FAILED)
                 return 0;
 
-        if (link->network->dhcp && link->network->dhcp_mtu &&
-            !link->original_mtu) {
+        if (!link->original_mtu) {
                 r = sd_rtnl_message_read_u16(m, IFLA_MTU, &link->original_mtu);
                 if (r >= 0)
                         log_debug_link(link, "saved original MTU: %"
@@ -1591,6 +1603,7 @@ finish:
 }
 
 static const char* const link_state_table[_LINK_STATE_MAX] = {
+        [LINK_STATE_INITIALIZING] = "configuring",
         [LINK_STATE_ENSLAVING] = "configuring",
         [LINK_STATE_SETTING_ADDRESSES] = "configuring",
         [LINK_STATE_SETTING_ROUTES] = "configuring",